Hot-air furnace



J. B. OLDERSHAW.

' yHOT-AIR FURNAGE.

No. 808,428. Patented Nov. 25, 1884.

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HOT-AIR FURNACE.

SPECIFICATION forming part of Letters Patent No.308,428, dated November 25, 1884.

Application filed February 28, lSSll. (Fo model.)

ments in Hot-Air Furnaces, of which the following is a specification, reference being had to the accompanying drawings, forming part hereof, in which- Figure l is a transverse horizontal section Io taken on the line a x of Fig. 2, and Fig. 2 is a vertical section taken on the liner a: of Fig. I.

Like letters of reference mark the same parts inall the figures.

' My invention relates to hot-air furnaces, and

i5 has for its object to increase the heating cai pacity by furnishing an increased supply of hot air with a less consumption of fuel than has been heretofore possible; and to that end my invention consists in the combination, ar-Ky 2o rangement, and construction of parts, which will now be described, and afterward specifically pointed out in the claims.

Referring to the drawings by letter, A is the jacket which surrounds the furnace. B

is the ash vpit or box, having door b, and to which the legs or supports b are attached. C is the fire-box,which is provided with an opening, c, to receive the fuel, closed by a door, c', and having a grate, c2. The sides of the re- 3o box are surmounted by a concentric ring, forming laterally-extending flanges (Lupen which,

at their outer edges,is mounted a cylinder, d',

extending to near the top of the jacket. Another concentric ring,fcl`-, surmounts the-cylinder d', reaching inward, aud from whose inner edge projects a cylinder, d", which reaches down to within a short distance of the ringflange d, and has its bottom closed by a plate,

E, which is sufficiently large in diameter to 4o ll the outer cylinder, d', and forms the top of the fire-box. This plate E is cut away at e, for a purpose hereinafter explained. Any, desired number of pipes or flues, F, reach from the interior of cylinder clto the exterior .i5 of the jacket, and a flue, G, extends from the interior of cylinder d to the exterior of the jacket on the side opposite to the supply-door c of the nre-box.

All the parts hereinbefore described may be 5o made of any material suited to t-he purpose,

and may be cast or otherwise made in as many pieces as may be desirable or convenient,

known manner. When in position, as described,yand re being kindled in the iire L box, the products of combustion will pass upward out of the fire-box through the opening e into the concentric smoke-box H H', thence around in either or bothdirections from H to H', and through the flue or pipe G. The heat of the fire-box and smoke-box will create au upward draft in the space I between these parts and the jacket, which will tend to compress the air in the top of the jacket, as at J. The interior space, K, surrounded by the smoke box, being also occupied by air, that portion of the air at the bottom thereof, being in contact with the intensely-heated top E of the lire-box, will be expanded in all directions, and as in any attempt to expand upwardly it will meet with the resistance ofthe compacted body vof air at J, it will rush out througli the'hotair flues or pipes F, to be distributed as desired. The air which is thus distributed will, in its passage over the course marked by the arrows t', become doubly heated, being first heated by contact with the sides of the fire-box and smoke-box, and then carried down, and before delivery to the iues be still more heated by contact with cylinder d3 and plateE on top of the fire-box. The passage of the heated air through the fines F will heat them, and thus give still more heated surface in the space I in the jacket. The smoke-fine also aids in this effect. By this arrangement it is impossible to deliver cold airthroughthe air-flues while any of the parts are heated, and a much greater supply of heated air is furnished than is possible with that class of furnaces,so commonly used,in which the air passessimply through the space I and is deliveredv through air-fines at the top of the jacket. j

The improvements herein described are equally applicable to stoves.

Having thus described my invention, what I claim, and desire to secure by Letters Patent,

1.4 Ahot-air furnace having a fire-box, a concentric smoke-box surmounting the same and encircling a chamber, K, from which the air-flues diverge, and a jacket surrounding the same, having no opening except at the IOO bottom, whereby the air received through the opening at the bottom of the jacket is carried 2 l 308,4,23 c ,A l" v upward betwecnthe jacket and re and smoke r through thesmoke-box and space I,4 andthe boxes, thence downward through said ehzunsmoke-flue `leading from the smoke-box ber K, and finally out through the ues, as through said space, as set forth. 1 Y set forth. Y In testimony whereof I have hereunto set 5 2. The combination, substantially as demy hand in the presence of two Witnesses. scribed7 of the fire-box, the concentric smokeboXsurmount-ngthe same, forming the cham- I JOHN Bf OLDERSHAW ber K, the jacket surrounding these pa1ts,r| Witnesses: forming the chamber or space I, the air-fines S. BRAsHEARs, io divergng fromv chamber K, and Apassing l JNO. T. MADDOX. 

